/sci/ - Science & Math

Hi /sci/. Hope this belongs here. I haven't done physics since highschool so please bear with me. The other day I learned the basics on how the AK-107's balanced recoil system works and I'm wondering if it could be simplified. The weapon is made by engineers and I'm not so I'm guessing the answer is no.
Pic (1) is a simplified view of the system. The bullet is propelled by high pressure gasses pushing it forward, some of these go up into the gas tube and push the blue part back. This is how many rifles work. In this case, though, they also push the yellow part, which acts as a counter-weight, forward. These two pieces act as racks, engaged by pinion gears (picture as a purple circle because I ran out of space) that keep them synchronized.
My question is: could it work if the gases didn't push the counter weight forward, as seen in pic (2)? The gases push the piston back, and the counter-weight, engaged by the pinions, have to go forward.
I'm sure it would go forward but maybe it would just act as dead weight if not propelled by the gases, rather than balancing the recoil? Is that part necessary?